Diaphragm pump



Patented Jan. 30, 1934 1,945,181 DIAPHRAGM PUMP 'William C. Carter, Flint, Mich. Original application February 23, 1928, Serial N 0. 256,720. Divided and this application February 18, 1933. Serial No. 657,357

1 claim. (C1. 10a- 150) This application is a division of my pending application Serial No. 256,720, for Pump 4for liquid fuel supply systems, led February 23, 1928.

One object of my present invention is to provide a diaphragm pump that is equipped with a novel means for controlling the position and ilexing of the diaphragm, whereby the life of the diaphragm is prolonged, or lthinner or lighter weight material may be used to form the diaphragm.

Another object is to provide a diaphragm pump that is equipped with a very thin fabric diaphragm and a novel means for maintaining the central portion of the diaphragm in correct polsition and also preventing said intermediate'portion from bending or flopping unnecessarily when the direction of movement of the diaphragm is changed at the end of its stroke in either direction.

And still another object of my invention is to provide a diaphragm pump, in which a diaphragm, formed preferably of fabric, is combined with accurately guided reciprocating members that co-act with stationary members to effectively support or back up the intermediate flexible portion of the diaphragm at any and all points in the stroke of the diaphragm, and cause said intermediate portion to bend or flex in a circular line of gradually increasing diameter'or gradually decreasing diameter, according to the direction of stroke of the diaphragm.

Figure 1 of the drawing is a vertical sectional View of a diaphragm pump embodying my present invention.

Figure 2 is an enlarged fragmentary sectional view, illustrating the means that is used to control the bending or flexing of f the intermediate portion of the diaphragm, showing the diaphragm at the end of its suction stroke; and

Figure is a similar view, showing the diaphragm at the end of its discharge stroke.

In the accompanying drawing which illustrates the preferred form of my invention, G designates the diaphragm of the pump, which is preferably composed of either one or a plurality of layers of fabric treated with a substanceA that will render the fabric impervious to gasoline or water, without making it rbrittle or inflexible, said diaphragm G being arranged so that it forms one wall of a pumping chamber 1 into which liquid is drawn when said diaphragm flexes in one direction, and from which said liquid is forced when said diaphragm exes in the opposite direction. The diaphragm G is disk-shaped and is herein illustratedY as being arranged vertically at one side of a cavity in the body portion H of the pump that constitutes the pumpingvchamber 1. The peripheral edge portion of said diaphragm is clamped between an annular part on the body portion H, .and a co-operating member I that serves as a support for the body portion H and also as a housing for a mechanically-operated member K which forms part of the mechanism for flexing or actuating the diaphragm, G. Usually, the housing member I will be connected to and mounted on the outside of the crank case of an internal combustion engine, the crank case having an opening through which a portion of the mechanically operated member K projects into the crank case so as to co-operate with a cam orthe like in the crank A case, as shown in Figure 1.

It is immaterial, so far as my present invention is concerned, what type .or kind of mechanism is used to actuate the diaphragm. The actuating mechanism herein illustrated come prises two compression springs 2 and 3 arranged on opposite sides of the diaphragm G. The spring 3, which is of greater force or strength than the spring 2, is used to impart a discharge stroke to the diaphragm vso as to create pressure in the pumping chamber 1 and expel the liquid from said chamber, and the spring 2 is used to flex the diaphragm in the opposite direction, so as to create a suction in the chamber 1 and cause the liquid to be drawn into said 85 chamber from a source of supply. Energy is stored up in the spring 3 by means of the rockable member K previously mentioned, which member K is herein illustrated as being provided with an arm 4 that co-operates with a cam or 90 other rotatable actuating device -5 in the crank case, and also provided with an arm 6 that en gages a cage or'guide 9 which encases the spring 3. When the cam 5 is in rotation the element K rocks back and forth and exerts pressure on the spring cage 9 in such a way as to cause said cage to reciprocate, and thus alternately compress the spring 3 and permit said spring to expand. When the element K rocks in a direction to permit the spring 3 to expand, the pressure 100 which said spring exerts on the diaphragm G imparts a discharge stroke to the diaphragm or moves said diaphragm to the left, looking at Figure 1, thus causing the spring 2 to be placed under compression. Thereafter, when the element 105 K rocks in the opposite direction, said element compresses the spring 3, and during this period in the cycle of operations of the pump, the spring I2 expands and flexes the diaphragm to the right,

thus causing the diaphragm to create a suction '110 in the chamber 1 of the pump. As is usual, the pump vis provided with a spring-pressed inlet valve (not shown) that opens automatically and admits the liquid to the chamber 1 during the suction stroke of the diaphragm G, and the pump is also provided with a discharge valve (not shown) that opens automatically and permits the liquid to escape from said pumping chamber during the discharge stroke of the diaphragm. v

The diaphragm G is combined with the body portion H and with the housing member I in such a way as to produce a slight buckle in the diaphragm, which insures a quick movement or sudden movement of the diaphragm each time it reverses or changes its direction of movement. In the pump herein illustrated the buckle in the diaphragm is produced by forcing the peripheral portion of the diaphragm into a circular recess, of slightly less diameter than the diaphragm, formed in one of the parts between which the peripheral edge portion of the diaphragm is clamped. Thus, -as shown in Figure 1, the portion of the supporting or housing member I that is arranged in opposed relation to the annular part on the body portion H that bears against the'peripheral portion of the diaphrag-m, is provided with a circular recess, designated by the reference character 21, of substantially the same depth as the thickness of the diaphragm, but of slightly less diameter than the diaphragm. In assembling the diaphragm with the parts with which itco-operates, the peripheral edge portion of the diaphragm is forced into the recess 21 in the supporting member I, thus causing the diaphragm to buckle slightly, and thereafter, said supporting member is connected with the body portion H by means of screws or other suitable fastening devices 22 that pass through the vsaid supporting member I and through a flange 20 on the body portion H at a point beyond the peripheral edge of the diaphragm, as shown in Figure 1.

As previously stated, the peripheral portion of the diaphragml G is clamped between opposed parts on the stationary members H and I. The central portion of the diaphragm is embraced by 4two reciprocating members J and J. The stationary clampingmembers for the peripheral portion of the diaphragm and the reciprocating members that embrace the central portion of the diaphragm, are so designed and proportioned that there is an intermediate portion of the diaphragm that is free to ex or bend back and forth when the pump is in operation, and thusprovide for the reciprocating movement of the central portion of the diaphragm engaged by the members J and J', relatively to the-stationary peripheral portion of the diaphragm clamped by the members H and I. In order to maintain the central portion of the diaphragm G in concentric relationshipwith its peripheral portion and also prevent the exible intermediate portion of the diaphragm from exing or bending excessively, or from bending or flexing unnecessarily and in such a manner that the bres of same are liable to fatigue andbreak down, I construct the reciprocating members J and J so that one or the other of said members will always be in direct slidingV engagement with a stationary portion or portions of the pump housing or casing, and I provide said members J and J with a pair of reversely-curved surfaces that co-act with a pair of stationary reversely curved surfaces to tion of the diaphragm at any and all points in the stroke of the diaphragm. In the form of my invention herein illustrated the members J and J' are provided at their peripheral edges vwith flanges which are in sliding engagement but not 1 in snug or fuel-tight contact with the body portion H and with the housing member I, respectively, as shown in Figure 1. Consequently, even though the diaphragm be formed ofv veryvthin fabric which has no inherent stiffness, the cen" 2 tral reciprocating portion of the diaphragm will be maintained in concentric relationship with the stationary peripheral portion of the diaphragm, because the members J 'and J are directly guided by the pump housing and one or 1 the other of said members (preferably both members) will always be in sliding engagement with a stationary portion of the pump housing.

The pair of stationary, reversely curved sur, faces previously mentioned, consist of convex i surfaces 30 and 30a carried by the housing members H and I, respectively, and the reversely curved surfaces with which they co-act, consist of convex surfaces 31 and 31a on the reciprocating members J and J respectively. 1(

Thel curvature of the curved surfaces just' referred to may be varied, but it is preferable to proportion or design said surfaces so that each surface has a drop equal to one-fourth of the stroke of the diaphragm and have the surfaces 1( 31 and 31L on the members J and J', respectively, located in such relationship with the surfaces 30 1 and 30Bi on the members H and I, respectively, that substantially the entire area of the exible intermediate portion of the diaphragm will 11 be backed up and supported, and said intermediate` portion eiectively held against movement when the diaphragm is at the end of its stroke in either direction. When the diaphragm is at the end of its discharge stroke or pressure stroke, 11 as shown in Figure 3, the movable, curved surface 31a co-acts with the stationary curved surface 30 to hold the flexible intermediate portion of the diaphragm in such a Way that when the stroke of the diaphragm is reversed, there is no liability 12 of said intermediate portion opping over and making an unnecessary bend, as would occur if no means were provided for holding the intermediate portion of the diaphragm against movement at this period in the cycle of operations of l2 the pump. At the beginning of the suction stroke,

i. e., when the members J and J start to move to vJ continues to move to the right, the intermediate portion of the diaphragm will, in eifect, be 141 pealed o'ff the stationary surface 30 and bent over the stationary surface 30a; and when the end of thel suction stroke is reached, the intermediate portion of the diaphragm will be clamped and held against movement, by the movable curved 141 surface 31 and the co-actingstationary curved surface 302. At the reversal of the stroke, or when the members J and J start to move to the left from the position shown in Figure 2, the pressure that is created in the pumping chamber 154 1 causesthe intermediate portion of the diaphragm to remain in engagement with the stationary surface 30, and when the member J' reaches such a position that the curved surface 31B thereon contacts the intermediate portion of the diaphragm, said intermediate portion will be bent over the surface 31, and the continued movement of the member J to the left will cause the intermediate portion of the diaphragm to be peeled off the stationary surface 30 and applied to the stationary surface 30, as shown in Figure 3, said curved surfaces 31a and 30 co-acting with each otller to prevent the intermediate portion of the diaphragm from opping over at the reversal of the stroke of the diaphragm. In addition to performing the functions above described, the accurately guided reciprocating members J and J cause the actuating force or pressure for the diaphragm to be centralized and applied substantially evenly to the diaphragm.

From the foregoing it will be understood that in my improved pump the central portion of the diaphragm is maintained in concentric relationship with the peripheral portion of the diaphragm, and the intermediate flexible portion of the diaphragm is eifectively held and prevented from iioppingI over at the reverse of the stroke of the diaphragm, by the members J and J' and the stationary portions of the pump housing with which they co-act. Moreover, the intermediate portion of the diaphragm is caused to flex or bend on a. circular line of gradually increasing or diminishing radius in such a way that the fibres of the diaphragm are not subjected to abrupt bends or injurious. strains. Consequently, the life of the diaphragm is materially prolonged and thinner or lighter weight material can be safely used in the construction of the diaphragm.

Having thus described my invention, what I claim as new andv desire to secure by Letters Patent is:

A fuel pump provided with a housing structure, a non-metallic, flexible diaphragm arranged so as to form one Wall of a pumping chamber, into and out of which fuel is drawn and discharged by the movement of the diaphragm, clamping members on the housing structure that embrace the peripheral portion of the diaphragm, reciprocating members engaging the central portion of the diaphragm and arranged in direct sliding contact with the housing structure, and reverselycurved surfaces on said housing structure and on said reciprocating members, located at opposite sides of the diaphragm, for the purpose described.

WILLIAM C. CARTER.

Asus 

